578 



NIACIN 



action of the toxicity of crystalline borrilidin in rats;^^ decreased serum 

 cholinesterasef * and an increase (with thiamine) of basal metabolic rate.^^ 



XIII. Requirements and Factors Influencing Them 



J. M. HUNDLEY 



A. ANIMALS 



Table XVII presents a summary of published information on the nicotinic 

 acid requirement of various species. The figures for tryptophan listed in 



TABLE XVII 

 Nicotinic Acid Requirement and Amount of Tryptophan Required to Replace 



Nicotinic Acid 



" Figures in parentheses are references. 



* Tryptophan can replace nicotinic acid in the mouse and cotton rat, but this has not been deter- 

 mined quantitatively. 



' The ability of tryptophan to replace nicotinic acid in the turkey has not been determined. 

 '^ Trypotophan does not appear to replace nicotinic acid in cats. 



">* J. M. Cooperman, S. H. Rubin, and B. Tabenkin, Proc. Soc. Exptl. Biol. Med. 76, 

 18 (1951). 



